Pseudohumicola cinnamobrunnea Sastoque, Cano & Stchigel, 2025

Sastoque, A. P., Cano-Lira, J. F. & Stchigel, A. M., 2025, Soil ascomycetes from Spain. XIV. The Chaetomiaceae of La Palma (Canary Islands), Persoonia 54 (1), pp. 93-117 : 106-107

Pseudohumicola cinnamobrunnea Sastoque, Cano & Stchigel , sp. nov. MycoBank MB 847930. Fig. 7 .

Etymology: From Latin cinnamomum -, cinnamon, - brunneae, brown, due to the colour of the conidia.

Typus: Spain, Canary Islands, La Palma, Fuencaliente (Los Canarios), isolated from soil of Teneguía volcano, 15 Jul. 2008, coll. M. Calduch & A.M. Stchigel, isol. A.P. Sastoque (holotype CBS H-25248, culture ex-type FMR 18980 = CBS 150900 ) .

On potato carrot agar after 2 wk at 25 °C: Mycelium composed of somatic hyphae hyaline, septate, branched, forming several spirals, smooth- and thin-walled, 1–2 μm wide. Conidiophores undifferentiated. Conidiogenous cells integrated to the vegetative hypha. Conidia holoblastic and 1-celled, solitary or less frequently in chains of two, sessile ( Fig. 7E ), on short conical denticles or on short (sometimes subglobose or obovoid) side branches from the hyphae ( Fig. 7F, G ), smooth- and thick-walled, covered by mucilaginous and dark brown substance, becoming verrucose to reticulate when old, sometimes intercalary (holothallic), then 1−2-celled, pale olivaceous brown to brown, globose, subglobose, obovoid, pyriform, less frequently ovoid, obpyriform or ellipsoidal, (4–)7–9(–10) × (5–)8–10(–12) μm ( Fig. 7E–G ). Acremonium-like synasexual morph and sexual morph not observed.

Culture characteristics (after 7 d at 25 ° C): Colonies on PCA 46–47 mm diam., circular and flat; margin filamentous and regular; surface showing white (4A1) aerial mycelium and grey (5B1) bottom only in the central area, surrounded by a cream (4A3) zone and yellowish white (4A2) margins; soluble pigment absent; reverse yellowish grey (4B2) in the centre, grey (5B1) and yellowish white margins (4A2). Colonies on OA 37–40 mm diam., flat, circular, and expansive; margin filamentous and regular; surface uncoloured with scarce floccose greyish white (4B1) aerial hyphae in the centre; soluble pigment absent; reverse uncoloured. Colonies on CMA 40–45 mm diam., circular and flat; margin filamentous and regular; surface hair brown (5E4) with scarce white (8A1) aerial hyphae in the centre, margins yellowish white (4A2); soluble pigment absent; reverse bronze (5E5). Colonies on MEA 45–46 mm diam., flat and circular; margin filamentous and slightly undulated; surface yellowish grey (4B2) with scarce and floccose white (8A1) aerial hyphae in the centre, surrounded by a pastel red (8A5) halo and pale yellow (4A2) margins; reverse light-yellow (4A4) in the centre, cream (4A3) and pale yellow (4A2) margins. Culture iconography after 2 wk of incubation on PCA, OA, CMA and MEA ( Fig. 7A–D , respectively). Minimum, optimum and maximum temperature of growth on PDA after 7 d: 12 °C, 30 °C and 45 °C, respectively.

Notes: Pseudohumicola cinnamobrunnea was located as a distinct species in a fully supported terminal clade together the ex-type strains of Humicola glauca CBS 462.76 and Pseudohumicola semispiralis CBS 723.97 (0.99 PP/94 % BS; Fig. 1 ). Pseudohumicola cinnamobrunnea differs from Pseudohumicola semispiralis by lacking a sexual morph (chaetomium-like in P. semispiralis ) and by the production pale olivaceous brown to brown sessile to stalked conidia (hyaline to olivaceous sessile conidia in P. semispiralis ) ( Udagawa & Cain 1969, Wang et al. 2019b).

Figures

Fig. 7. Pseudohumicola cinnamobrunnea CBS 150900. A–D. Colonies on PCA, OA, CMA, MEA (2-wk-old; 25 °C; surface, left; reverse, right). E. Conidia single cell, aseptate, sessile. F, G. Conidia single cell on short subglobose or obovoid side branches from the hyphae. Scale bars = 10 μm.

Fig. 1. Maximum likelihood of the tree obtained from the concatenated ITS-LSU-rpb2-tub2 (3215 bp) alignment of the nucleotide sequences from our strains and those retrieved from the GenBank. Bayesian posterior probabilities (PP) ≥ 0.95 and the RAxML bootstrap support values (BS) ≥ 70 % are presented at the nodes (PP/BS). Thickened branches indicate full support (PP = 1 and BS = 100 %). The new species and combinations are indicated in bold. T represents the ex-type strain of the species. NT represents the ex-neotype strain of the species.